Sulphurized lubricant



Patented June 17, 1941.

UNITED STATES PATENT OFFICE 2,246,415 SULPHURIZED LUBRICANT Ralph A.Potter, Berkeley, Calif., asslgnor to Union Oil Company of California,Los Angeles, Calif., a corporation of California No Drawing. ApplicationApril 10, 1939, Serial No. 267,187

6 Claims.

This invention relates to lubricants, including both oils and greases,which contain sulphur to impart extreme pressure characteristics such asimproved film strength, load-carrying capacity and wear resistance. Theobject of the invention primarily is to provide a product and a method-of procedure which will avoid difliculties heretobeen heretoforeencountered in attempting to sulphurize mineral oils directly.

Briefly stated, they invention resides in the em ployment of smallproportions of rosin'or rosin oil.or other rosin fractions or rosinacids or pine acids, in sulphurized mineral lubricating oils and inconnection with processes for producing such oils. All of these rosinmaterials or pine acids contain large proportions of abietic acids.

By employing rosin or rosin materials containing these rosin acids, theacceptability of the tities, for example 1% to 2%. the acceptability ofthe oil itself for sulphur is increased by about 1% or sometimes 2% ofadditional sulphur. the same time the rosin material added will acceptabout 40% of sulphur based upon the content of rosin material. By theexpression "acceptability for sulphur is meant the capacity to receivesulphur in solution or in chemical combination according as the actualfact may be,

-without substantially increasing the sludging tendencies of thesulphurized oil over the sludging tendencies of the original minerallubricatingoil "employed. Observing these principles, the sulphurcontent for a finished lubricating oil will normally be in the range ofabout 1% to 6% or 7% of the composition, and the rosin content willnormally be in the range of about 0.5% to 6% or 7%. It will beappreciated that a sulphur content of about 2% to 5%, where about 3% ormore sulphur is present, is accounted for by the .solvent power of theoil itself for sulphur, in-

cluding the increased acceptability of the oil for sulphur where rosinmaterials are present.

Therefore, invention resides in these proportions. Also lubricatingconcentrates, which might possibly be used as lubricants in certainconnections, may be made containing increased quantities of both rosinmaterial and sulphur, which concentrates may be subsequently dilutedwith oil to produce the desired finished product.-

These concentrates will extend up from the limits of 6% or 7% for eachof the sulphur and rosin materials in a finished lubricant to as much as20% sulphur with 4.5% rosin and only 35% mineral oil in the concentrate.As the sulphur content is increased, it is necessary to increase thecontent of rosin material correspondingly in order to avoid excessivesludging of the product,

that is sludging appreciably greater than the sludging property of theunmodified lubricating oil itself.

Therefore, the invention resides further in lubricants comprisingmineral lubricating oils, from about 0.5% to about 45% of rosinmaterials and from about 1% or 2% to about 20% of sulphur in solution inthe lubricant. The invention further resides insuch lubricants whereinthe rosin content is increased as the sulphur content is increased toinsure against substantial sludging tendencies. Thus, the inventionresides also in lubricants comprising primarily mineral oil with about10% or 12% sulphur and about 20% rosin material up to about 20% sulphurwith 45% rosin materials. The invention also resides in methods ofpreparing such lubricants wherein the materials are heated at elevatedtemperatures in the order of 250 F. to 400 F. to obtain the desiredsolution or chemical combination of the sulphur. The invention residesfurther in so treating the materials by combining the rosin materialwith lubricating oil and then introducing the sulphur, the batch befmgheated for an extended time to accomplish'the proper incorporation ofthe sulphur.

In operating according to the present invention, the rosin or abieticacid material in required amount (for example 1%) is added to minerallubricating oil, and preferably to this mixture there is added therequired amount of sulphur (for example 3%) for the sulphurizedlubricant sought to be produced. Any type of mineral lubricating oil may.be employed, the only difference being that different minerallubricating oils possess slightly different degrees of acceptability forsulphur. The rosin material may be any commercial material containingabietic acid such as rosin, kidney rosin oil, commercial abietic acids,pine acids and the like. These materials are then heated together in asuitable kettle, preferably a pressure kettle, whereby superatmosphericpressures may be obtained if desired, any suitable heating means beingemployed such as fire or steam coils. The contents of the kettle areraised to temperatures which may vary somewhat in accordance with theparticular materials being employed. Temperatures between about 250 F.and 400 F. are employed. The temperature is maintained within thatrange, for example around 300 F. or about 290 F. to 310 F., withagitation for a sufficient length of time to effect the degree ofsulphurization which can be accomplished with the sulphur which has beenadded. By operating with these materials, the length of time fortreatment may be increased beyond times heretofore ordinarily used forsulphurization and, by reason of the presence of the rosin material, theextent of sulphurization is increased without producing products havingexcessive sludging tendencies, as'

above indicated. The time of treatment will vary ordinarily within therange of about three hours to nine hours, e. g. six hours. By heatingunder these conditions, the sulphur apparently is primarily chemicallycombined with the rosin oil, and also with the lubricating oil to theextent of the 2% to 5% which the lubricating oil will accept as has beenindicated. secondarily, some of the sulphur apparently is physicallycombined in the mixture, possibly as by solution in the oil or in therosin material. This incorporation of the sulphur into the lubricant isgenerally herein referred to as solution, which term is intended toinclude the solution or chemical union or both according to whatevercondition exists by reason of the treatment at elevated temperature.

The resultant oils containing the proper pro portion of sulphur androsin materials as indicated are stable from the standpoint of theirsulphur content, and in use do not sludge appreciably beyond the normalsludging tendency of the-unmodified lubricating oil itself. The relativeproportions of sulphur and rosin materials to be employed to obtainthese stable nonsludging oils were indicated above, it being necessary,as also indicated above, that the proportions of rosin materials beincreased adequately as the sulphur is increased to insure proper unionor solution of the sulphur with the mixture of mineral lubricating oiland rosin materials in order to form the stable products having thedesired substantially non-sludging tendencies.

In general, when producing a finished lubricating oil, it is preferredto limit the sulphur content, and consequently the rosin content, torelatively low proportions, inasmuch as these ordinarily are adequate toimpart the desired extreme pressure characteristics sought inlubricating oils of this type, for example in the preparation of hypoidgear lubricants. This desired limitation of the abietic acid of therosin materials may be easily accomplished for the reason that theabietic acid molecules (C19H29COOH) are capable of accepting one or manysulphur atoms according to the degree of sulphurization required in thefinal product. Thus, for a finished oil a typical average rosin acid orrosin material content to be employed would be about 1% or within apractical range of probably about 1% to about 2%. In this case, from 1%to 3% or 4% of sulphur for each percent of rosin may be introduced, themineral oil itself taking up someof the sulphur. Typical examples willcontain:

M i n e r a l lubricating Instead of preparing the finished lubricantcontaining only 1% or 2% rosin and 3% to 5% sulphur, a finished oil maybe produced containing more rosin and more sulphur if desired. Forexample, up to 6% or 7% or possibly a little more of each of the sulphurand rosin material. In many instances, however, it is preferred tomanufacture lubricating concentrates containing much smaller proportionsof lubricating oil, the additional lubricating oil to be blended intothe concentrate at some future time. Thus, a concentrate containingabout40'% or possibly a little more of rosin material, about 40% oflubricating oil and about 20% of sulphur may be produced. It is to berecognized that here, after accounting for the sulphur taken up by thelubri- 1 cating oil itself, the remaining sulphur content ordinarilyshould not exceed about 40% of the rosin material content. While itispossible at least for some uses, that the sulphur content based on therosin material may be greater than 40%, nevertheless on the average thissulphur limit should be observed where stable substantially nonsludgingproducts are required. on this basis, a rosin material content of about20% of the total would support a sulphur content, including thataccepted by the oil itself, of about 12%. Of course, these limits arenot critical because of the fact that, as above indicated, each abieticacid molecule is capable of accepting not only one but many sulphurmolecules. In general, however, the invention lies in the incorporationof sulphur, as above indicated, into rosin and mineral oil mixtureswherein the maximum of rosin material indicated for any given sulphurcontent is employed so as to insure stable substantially non-sludgingproducts, the percentage content of rosin being in the order of from0.5% to 40% or possibly 45% with a corresponding sulphur content withinthe range of about 1% to about 20%, the rosin material contentincreasing as the sulphur increases, it being recognized that from about2% to perhaps 5% of sulphur is accepted by the mineral lubricating oilitself.

With respect to rosin materials which may be used according to thisinvention, kidney rosin oil, which is a rosin distillation product wellknown in the industry, has been indicated above and is generallypreferred, especially for sake of convenience. Nevertheless, I may alsouse other sources of rosin acids or pine acids, such as wood rosin, gumrosin; other rosin oils than that mentioned, commercial rosin acids orabietic acids, pimaric acid, pseudo-pimaric acid and the variousdistillation products of these materials in crude or purified form, andalso various modified rosin acids, such as modified rosins or modifiedabietic acids or derivatives thereof known on the market. Rosin acids orpine acids are generally understood to include primarily abietic acids,and also pimaric acid, pseudo-pimaric acid,

sapinic acid and the like and various isomers and of sulphur employed,these as mixtures 01 Mid-Continent steam refined oils,

Pennsylvania neutral oils and western lubricat ing oils of thenaphthenic type suchas above mentioned, these being employed inapproximately equal proportions or otherwise as may seem fitting. Alsothe heavily solvent treated oils 01 high parafllnic oil content, orother highly refined parafllnic type oils, may be usedalone or inadmixture with other lubricating oils as above indicated.

In the heat treating operation the temperature on the average will bearound. 300 F, or from perhaps 290 F. to 310 F. Ordinarily the rosin oilis added to the lubricating oil in the creasdtendency' to sludge andloss in loadcarryihg capacity. The optimum time is determined byremoving samples of an experimental mix' and adding corrosion inhibitor,(lead naphthenate) and determining load-carrying capacity and tendencyto sludge and corrosiveness to steel.

From those results the. time required for a given mixture is chosen. Thecorrosive street and sludge-forming tendencies of the oil are determinedarbitrarily by adding 5% of lead naphthenate to the oil as a corrosioninhibitor, im-

kettle, and if other rosin products, such as rosin itself or' commercialabietic acid, are used, the temperature may be raised with agitationuntil solution of the rosin materl I is effected. 'The powdered flowersor sulphur are ordinarily added to the oil and rosin product soiutionafter the latter has reached the for example 300 F. Agitation ismaintained for an appropriate period of time, for example six hours,until'the sulphur which has been added, for example 2.5%, has combinedwith the oil. In a particular instance, 965 parts of bright filter-edPennsylvania lubricating all stock was combined with parts (1%) ofthe=rosin distillation product known as No. 56 kidney rosin oil, andthis mixture then heated to 300 F. to 310 F., whereupon parts or flowersof sulphur (2.5%) were added. and the heating continued with agitationfor six hours. This sulphurized material was cooled and 5% of leadnaphthenate was added as a corrosion inhibitor.

While variations in temperature, and in sulphur content, and in the timeoi treatment are sometimes necessary according to the oils used orthearosin material incorporated or the amount will be -readilyascertainable by any skilled lubricant manufacturing operator,especially because 01 the fact that this procedure involving theemployment of rosin oil or other abietic acid or similar'rosinacid-conoperating temperature,

mersing polished steel strips in portions of the oil with and withoutthe addition 01. 5% of distilled water to the oil, maintaining atemperature of about 180 F. for 16 hours, and then observing the flectof such treatments on the steel strips. An oil to be consideredfullyacceptable should not deposit any sludge-like material or blacken thesteel strips to any noticeable extent, even in the presence of water.

The operations may be modified in certain connections if desired, forexample by the use 01' catalysts such as halogens or the variousmetallic halides (e. g. 0.1% of preferably alkali halides) to increasethe reaction rate, or by the use of closed kettles to eliminate air, asmay be convenient to speed up the reactions especially where highlyrefined oils are employed such as highly solvent treated naphthenlc baseoils or highly purified parafllnic base oils.

It will be recognized, of course, that where a given percentage ofsulphur is indicated as being added to the'charge, a small proportion ofthe sulphur is normally lost as hydrogen sulphide during the operation,and a correspondingly lubricants tester at 1000 R. P. M. with a loadingrate of 83.5 pounds per second and a rubbing ratio of 14.6 to 1. Such atester is found tiescribed in the S. A. E. Journal for July, 1936,

talning material, has such a wide range of permissible or optimumheating conditions that no difficulty whatever will be experienced. Inother words. regardless of the oil stock, or the amount of sulphur, thetemperature limits will usually lie within the range of 250 F. to 400 F.above indicated, and the heating time will nearly always be found to bewithin 3-to 9 hours or at least within a maximum range of 2 to 16 hours.Completion of the operation is readily determinable by tests outlinedbelow.

For every particular mixture of oil, rosin and sulphur there is anoptimum length of time to react at a given temperature in order to getmaximum load-carrying capacity and minimum sludging. Too short' a timeof reacting gives all which is too corrosive and has a tendency to de--posit sulphun Too long s. time leads to iii-'- pages 293 to 290 (vol.39). Products according to the invention do not ofier the objections ofprecipitating sulphur or sulphur crystals or yielding insoluble sludgesupon standing or in operation, and when the corrosion inhibitor agent isintroduced, they yield material also non-corrosive to steel in thepresence of water. With reference to corrosion. inhibitors, thepercentage of lead naphthenate employed may be varied from the 5%mentioned within a range. between about 4% and 10%. As substitutes forlead naphthenates, other soaps such as zinc naphthenate, magnesium,naphthen ate and lead oleate may be used, and other corrosion inhibitingmaterials such as zinc octyl this phosphate may sometimes be employed.

It is to be understood that these disclosures are illustrative of thegeneric invention hereof and are not to be taken quired by the priorart.

I claim:

1. Alubricating concentrate comprising in the neighborhood of 45% rosinmaterials, 20% sulphur and 35% mineral lubricating oil.

2. A lubricant comprising mineral lubricating oil. rosin materials-insolution in the oil, the rosin materials containing sulphurapproximating d0% W w u as limiting except as re- 01 said rosinmaterials, and the oil containing additional amounts-o! sulphur insolution therein in the order of 2% to 5%y 3; A lubricant comprisinimineral lubricating solution in the oil calculated on-the basis or thein oil content of the lubricant. 4

Patent No. 2-,21 6,l;15.

CERTIFICATE OF CORRECTION..

RALPH A. roTTE'R.

5. A lubricating composition comprising 'ni'ineral lubricating 011,about 1% of rosin n aterials containing abietic acid and about 3% ofsulphur in solution in the lubricant.

5 6. A. lubricating oil comprising" about 96% mineral lubricatingoil,about 1% of rosin material and about 2% to 5% of sulphurincorporated in the lubricant. i.

i RALPH A. PQTI'ER.

It is hereby certified that error appears in the printed-specificationof the above nurnbered patent requiring correction as follows: Page .l,first dolmnn, 'line ho, for "1% to 2%" read "19; or 2%--; page Lt, firstcolumn,

. line 8, claimigfor the claim reference numeral "10" read -5- and-thatthe said Letters Patent should be read with this-correctiontherein thatthe same may, conform to" the record of the case in the Patent Office.

Signed and sealed. this Lith 'day of Novariber, Ac D, 19in.

(Seal) 4 Henry Van Arsdale, Acting Gemmissioner of Patents.

CERTIFICATE OF CORRECTIONL I Patent No. 2,2l 6,L;15. June 17,- 191g.-

RALPH A. 30min.

It is hereby oertified that error appears in the printed-specificationof the above numbered patent requiring correction as follows: Page 1,first dolumn, line LLO, for "1% to 2% 'read "1% or 2%-'-; page 1;, firstcolumn,

. line 8, claim l for the claim reference numeral "-10" read ---5--epithet .the said Letters Patent should be read with this correctiontherein that the same may Conform to the record of the case in thePatent Office.

Signed and sealed. this hth day of November, 'A. D. 1915..

Henry Van Arsdale, (Seal) Acting Commissioner of Patents

